joining us now is david cullen. he spent years as a denver journalist researching and reporting on the columbine shootings. he wrote the book "columbine." thank you for joining me tonight in these difficult circumstances. >> thank you for having me. >> is this the right question to ask? is there anything about the greater context that can inform the way we process what happened today? >> i think that's exactly the right question. you sort of took my breath away going through that litany. i kind of wasn't prepared because -- well, we all lived through all of those, and a lot of those names i know. but i think it brings home the point even more that there are things to be learned here that we haven't really stepped up to learn. and i think the biggest single thing is we do need to look at the big picture. because when any one of these things happens, people feel like they want to know why. like why did this happen. the small why of why did this happen and they're looking at the bigger why, which is why does this keep